A vehicle seat of this type providing entire satisfaction is known in FR 2 900 105. In the known vehicle seat, the retaining member has the form of a retaining cam pivotally mounted on the seating portion below one end of the frame of the backrest, and coming into retaining position when the disabling member passes from the inactive position to the active position. A pusher is pivotally mounted on the backrest in order to move the retaining cam during the return of the backrest towards the upright position.
The disabling system has a structure such that mounting it on the frames of the seating portion and of the backrest is imposed by constraints in terms of relative positioning, and can hardly be adapted to place the disabling system in different portions of the seat.